With cable winches for large cable lengths it is difficult to wind-up the great amount of cable or the large length of cable onto the cable drum correctly while designing the cable winch with compact dimensions. Large-scale cable winches for deep-sea applications frequently require cable lengths exceeding 1000 m or even several thousand meters to be able to lower the load hook to a sufficient depth below the water surface. In order to control the winding proportions on the drum as desired, a long cable drum is preferable, which makes the cable winch rather bulky, however. As a result, the cable winch will be quite wide, which may exceed the desired maximum crane width or will require an excessively large envelope circle when rotating the crane to prevent collisions.
To alleviate such excessive widths and the problems resulting from collisions, it had already been proposed to simply shorten the length of the cable drum accordingly so as to have a cable drum design with narrower dimensions overall. With long cable lengths, however, several cable layers have to be wound on top of each other, which has the disadvantage that the winding operation can no longer be controlled, producing a very large winding diameter, because more cable layers must be wound on top of each other. This larger winding diameter results in greater output torques and at the same time also in greater loads on the end discs, because the wound-up cable layers support themselves laterally against the end disc.
The excessive width problem with such large-scale winches, which have a sufficient cable drum length to lessen the aforementioned winding problems, is also aggravated by the fact that drive assemblies are normally configured to be arranged on the outside, which frequently project considerably beyond the end discs and even still beyond the bearing shields on which the cable drum is pivoted.
It had in fact already been considered to incorporate the drive unit inside of the cable drum. But this has various drawbacks compared to an external configuration of the drive assemblies, such as with respect to installation and ease of maintenance as well as torque transmission. With large-scale winches of the cited kind it is advantageous to arrange the drive assemblies outside of the cable drum in the vicinity of the periphery of the end discs of the cable drum, wherein in particular a sprocket connected with the aforementioned end discs or which is formed by the end discs themselves can be used, which sprocket is in engagement with an output wheel of the drive assemblies. In this manner, the drive forces or the drive moment can be controlled precisely, wherein the rotational speed of the output wheel of the drive unit can be geared down once more with respect to the cable drum by appropriate diameter ratios, achieving a high level regarding ease of assembly and maintenance.
Frequently, a large axial projection of the drive assemblies results with such sprocket-type large scale cable winches, because in addition to the motor itself, the drive assemblies sometimes require a reduction gear having quite a long design to be able to convert the drive speed of the motor as desired.
The object of the present invention is to provide an improved cable winch of the cited kind, which avoids the disadvantages of the prior art and develops the latter in an advantageous manner. In particular, a cable winch with an external drive and which can be assembled and maintained easily is to be provided, which can be constructed with sufficient cable drum length despite the favorable winding proportions and which does not have excessive width to impede the crane's range of motion.
According to the present invention, the aforementioned problem is solved by a cable winch as cited in claim 1. Preferred embodiments of the invention are the subject of the dependent claims.
To utilize the available installation space on the cable drum, it is proposed to split-up the motor and the gear mechanism of the at least one drive unit onto different sides of an end disc of the cable drum. According to the present invention it is envisaged that the output wheel of the drive unit is arranged between motor and gear mechanism and that the motor and the gear mechanism extend towards different sides of the end disc. Because of the split-up configuration of motor and gear mechanism onto different sides of the respective end disc of the cable drum, it is possible to prevent an excessive projection of the drive unit beyond the front end of the cable drum on the one hand, while on the other any collision problems in the space between the end discs because of an optional additional drive unit or other components, is prevented. The available installation space between the end discs is utilized optimally, while at the same time it is possible to obtain good accessibility both to the motor as well as to the gear mechanism and therefore a high level regarding ease of assembly and maintenance.
In developing the present invention, it may have been implemented in the arrangement of the at least one drive unit such that the motor and the gear mechanism of the drive unit extend to opposite sides of a bearing shield, on which the cable drum is pivoted and on which the drive unit can be supported or mounted.
For this purpose, the split-up of motor and gear mechanism relative to the sides of the return discs and/or sides of the bearing shield can in principle be implemented differently. The gear mechanism can extend towards the outside of the end disc of the cable drum and/or of the outside of the bearing shield, for example, while the motor extends towards the inside of the end discs and/or the inside of the bearing shield. In developing the present invention, it is also possible that the gear mechanism can extend towards the inside of the bearing shield or the inside of the end disc, however, while the motor is arranged on the outside of the end shield or bearing shield. The latter configuration is particularly advantageous, if the gear mechanism assembly extends longer axially than the motor, so that the axial projection of the drive unit beyond the cable drum or the bearing shields is particularly small and the installation space between the end shields of the cable drum is utilized optimally. The energy supply of the motor can moreover be ensured in a particularly simple manner, if the motor is arranged on the outside of the end discs or of the bearing shield, for example by means of energy supply lines laid along the bearing shield.
In principle, the motor can be designed differently, for example an electric motor that is supplied via an electrical line or a hydraulic motor that is supplied via a pressurized fluid line.
In order to be able to arrange the output wheel of the drive unit compact between motor and gear mechanism without wasting radial installation space, the output wheel can be formed advantageously as hollow component and have an opening recess, through which a drive shaft extends that can be rotated relative to the output wheel, which drive shaft connects the motor on the one side of the output wheel with the gear mechanism on the other side of the output wheel. Advantageously, for this purpose the aforementioned drive shaft can essentially extend through the entire gear mechanism unit and be connected with an input element of the gear mechanism, which input element is arranged on an end section of the gear mechanism facing away from the output wheel or from the motor.
The aforementioned output wheel and/or the drive shaft which extends through the output wheel can be advantageously arranged approximately coaxially to the main axis of the drive unit, particularly approximately coaxial to a motor shaft and/or a main axis of the gear mechanism. A radially offset configuration would also be possible as an option, but wherein for attaining a slender design of the drive unit, a coaxial configuration of the output wheel and of the drive shaft extending through it is advantageous.
The drive moment originating from the motor is advantageously fed into the gear mechanism on a side of the gear mechanism facing away from the motor. As a result, a brake can be easily integrated into the drive unit, which, based upon the captured forces, can advantageously engage a gear or drive element onto which a relatively small, particularly the smallest occurring torque, is applied. The brake can in particular be able to be coupled to the aforementioned drive shaft or to the input element of the gear mechanism connected therewith, to be able to decelerate the cable drum geared-down appropriately utilizing the gear stage, so that a drum element induced by the pull of the cable only acts on the brake or has to be captured by it.
Advantageously, the aforementioned brake can be arranged on the front side of the gear mechanism unit facing away from the motor, as a result of which the brake is well accessible from outside and can be easily serviced, or assembled and dismantled.
If the brake is applied, the motor can also be demounted for maintenance or in case of emergency, although a load (torque) may have still be applied on the cable winch.
In developing the present invention, the drive unit can have a modular design, wherein a first assembly is formed from the gear mechanism, on the front side of said assembly a second assembly formed by the motor is mounted detachably and/or on the second front side of which a third module formed by the brake is mounted detachably. In particular, the motor, the gear mechanism and the brake can form three block-like assemblies, which are essentially arranged sequentially coaxial reciprocal, wherein particularly the gear mechanism can be arranged between motor and brake.
In developing the present invention, a detachable connection transmitting the torque can be provided preferably in the form of a plug-in connection between the drive shaft extending through the drive wheel of the drive unit, on the one hand, and the motor on the other and/or between the aforementioned drive shaft and the brake in each case, so that motor and/or gear mechanism can be dismantled easily and the drive shaft can remain as a fixed constituent part of the gear mechanism unit and/or in the gear mechanism, even when the motor or the brake are detached. The plug-in connection can be designed axially detachable, i.e. in the longitudinal direction of the shaft.
The aforementioned plug-in connection can in principle be designed differently, for example in the form of a spline-shaft hub profile or a polygon shaft boss joint.
The gear mechanism of the drive unit can have different variants. To facilitate the previously described arrangement of the output wheel between motor and gear mechanism and the transfer of the motor moment via the output wheel to the gear mechanism unit, in particular by means of the aforementioned penetrating long drive shaft, the gear mechanism can be designed as planetary gearing, preferably in form of a multistage planetary gearing configuration, the input element of which can be connected with the aforementioned, motor-linked drive shaft and the output element of which can be coupled with the output wheel of the drive unit. In this context, different planetary stage elements can be selected as input elements and output elements, depending on the desired gear ratio. To be able to realize a high step-down or step-up ratio in a space-saving configuration, depending on the viewing direction, in an advantageous refinement of the present invention, the sun gear of a first planetary stage can be connected with the motor-linked drive shaft and/or the output wheel of the drive unit can be coupled with a second or further planetary stage.
If multiple planetary stages are provided, they can be reciprocally coupled in different ways. The planet carrier of a first planetary stage can be coupled with the sun gear of a secondary planetary stage, for example, wherein the ring gears of both planetary stages can be fixed on the gear case. Other configurations are possible in principle, however, depending on the desired gear ratio.
In developing the present invention, in that context all stages of the planetary gear can be arranged on the same side of the output wheel of the drive unit. In an alternative development of the present invention, the gear mechanism can be also designed such, however, that the output wheel of the drive unit is arranged axially between two stages of the planetary gear.
The transmission of force or torque from the output wheel to the drive unit onto the cable drum or the drive wheel connected therewith can in principle be done in different ways, for example frictional, by a pair of friction wheels revolving together or a transmission belt stage, however by means of a positive joint, which in particular can be accomplished by a meshing gear pair or optionally by a chain drive.
In particular, the output wheel of the drive unit and a drive wheel coupled with the cable drum are forming a sprocket stage, which can advantageously be in engagement.
The aforementioned drive wheel connected with the cable drum can be integrated into one of the end discs of the cable drum, for example by a tooth profile on the outer perimeter of the end disc. The aforementioned drive wheel will advantageously be designed as sprocket which can be rigidly attached onto one of the end discs of the cable drum. In principle, however, the aforementioned drive wheel can also be designed separately from the end disc and be connected with the cable drum body in a different manner, for example by a direct connection with the drum body or by attachment onto a drum flange.
In developing the present invention, the drive unit can be arranged radially outside of the cable drum, in particular in the area of the outer perimeter of the end discs of the cable drum and can extend through a bearing shield arranged adjacently to the respective end disc or extend beyond the aforementioned bearing shield. The aforementioned bearing shield can have a bearing recess, into which the drive unit can be arranged or installed.
In the following, the present invention is explained in detail, using preferred embodiments and associated figures.